For those who wish to extract the most performance out of an aircraft EXEMPT from the new international regulations, there are many options using racing quadcopter motors, esc, and batteries.
My fastest model uses a 350 mah EIGHT cell lipo that can sustain 20a+ or burst 40 amps.
At half stick, it launches straight up.
Turns 3.5x5" prop over 50k with over 4:1 thrust..

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Here is an early evolution of my sub 250 gram speedmodels, 1.5 yr ago.
Only 177 grams with 370 mah 6s.
High winds and use of speed range show good flight character and high efficiency.
That was less than 280 mah flight...
3s prop setup in pic..

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Who wants to go 180mph+ for $100?
Check out what is going on in Germany..http://speedcroco.de/FDD.html
To beat the regulations, they decided to form an under 250 gram speed competition.
I would love to see some interest for this stateside, so we can form our own events.
In the meantime, I am testing 8s power systems, and new designs..

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Here is the first 30" design running a DYS 2100kv, 34g motor on 650 mah 8s and 4x3.3 APC.
14-15 ounces auw. Max 25a/800w.
Much less draw in air as burst flights like the video use only 500 mah in 4 minutes!!
(Video cut short)

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Over one hundred tested flights on 3, 4, 6, 7, and 8s on one test plane!
7s is the sweet spot, but 6s gives continuous wide open throttle.
7s goes 130 mph at HALF throttle and pulls away from that comically fast going to full stick.. while still being light enough to fly slowly.
28.5" 13.5 ounce.
Here is what only 550 mah of bursts look like....

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Going well on 7s, but 6s with larger prop is the sweet spot, being lighter with the same thrust.
All prototypes are flying well in the lingering summer heat.
New batteries and more powerful designs coming in time for cool fall air.
Working to get 8s perfected.
Here is prop failure and motor shed after a couple short bursts...

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Here is a twin 1500w potential system.
I aim to be a leader in power to weight, with a full 3000w+ static @ only 22.5 ounces!
Only 7 flights so far with 1500w total max.
Update later with more pics, tests, and video.
Update.. needed caacitors to run well on 6s..
Stuffed all I could inside the nacell.

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About as high power to weight I have seen in person..
Video is over 1500 watts static @24.5v and 13 oz with 870 mah pack. (Yes, tested to over 60a)
15-25mph cross wind.
Launch into loop at only 40% throttle...
5 minute flight was 700mah/870!
Fastest passes at 3:00.
1.2 second delay on throttle, now tuned to .5.
(Now faster)
Everthing runs reasonably cool..

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These are the latest in an evolution of homemade micro pylon/hotliners spanning 24-27.5", and weighing 165-249 grams rtf.
They are foam core with balsa, using glass and carbon on the fastest version.

The goal is to achieve better than 1600w/lb by a good margin, as this appears to be the upper limit for high$$ hotliners.. all this UNDER the FAA regs or under 250 grams!
I am currently at 800w/249g with a 1000w++ setup coming..